From: Phil Frederick (flosofl@gmail.com)
Date: Wed Apr 26 2006 - 09:43:01 EDT
On 4/24/06, Robert J. Kraus <rkraus@telcomtex.net> wrote:
> To me it does look like a hash of some sort. Now that you have the known
> password and the hash you can take that information and reverse engineer
> the hashed answer.
>
> I am curious to see how they hashed it and what algorithm they used.
> Once you have the hashing algorithm you can use that to unencrypt any
> passwords in the file.
Hashes are one way functions. You cannot work backward (or even
reverse engineer - what would be the point?) from a hash and "decrypt"
password. Even if the the hashing algorithm is MD5, SHA-0/SHA-1
(which have been shown to have collision weaknesses), finding a
collision is unlikely. Reverse engineering is really not the answer
(sort of).
The most likely course would be to use a rainbow table or a dictionary
attack. Use the known password and generate hashes using the
different algorithms (MD5, SHA-0, SHA-1, TIGER, etc). When you find a
match with the stored hash, you know the algorithm in use. Then all
that is needed is start slamming a dictionary against the rest of the
hashes, try some brute force variants. It gets a little more
difficult if it turns out they are using a salt to XOR the password
before the hash. Sometimes you can discover the salt by tracing the
program execution in a debugger - but it's a real pain.
I would also take images of the machine's memory. You would be
surprised how many plaintext information floats around there. In my
work I have found a few systems that use strong hashing/encryption
algorithms vulnerable due to poor protocol implementation.
------------------------------------------------------------------------------
This List Sponsored by: Cenzic
Concerned about Web Application Security?
Why not go with the #1 solution - Cenzic, the only one to win the Analyst's
Choice Award from eWeek. As attacks through web applications continue to rise,
you need to proactively protect your applications from hackers. Cenzic has the
most comprehensive solutions to meet your application security penetration
testing and vulnerability management needs. You have an option to go with a
managed service (Cenzic ClickToSecure) or an enterprise software
(Cenzic Hailstorm). Download FREE whitepaper on how a managed service can
help you: http://www.cenzic.com/news_events/wpappsec.php
And, now for a limited time we can do a FREE audit for you to confirm your
results from other product. Contact us at request@cenzic.com for details.
------------------------------------------------------------------------------
This archive was generated by hypermail 2.1.7 : Sat Apr 12 2008 - 10:55:52 EDT